Processes for alkylating a variety of alkylatable aromatic compounds by contacting such compounds with a hydrocarbon radical providing source such as an olefin or alcohol are widely known. Typically, alkylatable aromatic compounds are mononuclear aromatic compounds themselves or those substituted with a hydroxyl, amine or an ether group. The alkylation has been carried out in the presence of homogeneous and heterogeneous catalyst systems.
Ring alkylated aromatic amines have been some of the products produced by alkylation procedures. Ring alkylated aromatic amines have a variety of uses in chemical synthesis. Some of the early uses were intermediates for substituted isocyanates, herbicidal compositions, dyestuffs and textile auxiliary agents. More recently aromatic amines have been utilized as chain lengthening or cross-linking components in polyurethane systems. These are commonly referred to as chain extenders.
Representative references which illustrate some of the early processes in forming ring alkylated aromatic amines are:
British Pat. No. 414,574 discloses the reaction of aniline with various olefins, e.g., cyclohexene and alcohols, e.g., butanol in the presence of a neutral or weakly acidc catalyst system commonly referred to as hydrosilicates at temperatures from 200.degree.-270.degree. C. Ortho and para-cyclohexylaniline, N-cyclohexylaniline, N-butylaniline and para-methyl-ortho-cyclohexylaniline and N-cyclohexyl-para-toluidine are listed as representative products.
British Pat. No. 846,226 discloses ring alkylation of aromatic amines with olefins using active, substantially neutral bleaching earths of the montmorillonite type as a catalyst.
German Pat. No. 1,051,271 discloses the ring alkylation of aniline with an olefin, e.g., ethylene, in the presence of kaolin or in the presence of aluminum and aluminum alloys. Alkylation with higher olefins, e.g., propylene, butylene, etc., was carried out in the presence of Friedel-Crafts catalysts or bleaching earths under liquid phase conditions at temperatures from 150.degree.-350.degree. C. Examples of catalytic systems included aluminum chloride, zinc chloride, boron trifluoride, sulfuric acid, phosphoric acid and bleaching earth. Ring alkylation at the ortho-positions was predominant, although other products such as the di and tri-alkylated aniline product were produced.
In an article by Zollner and Marton, Acta Chim. Hung. Tomus 20, 1959 (Pages 321-329) the vapor phase alkylation of aniline with ethanol was effected in the presence of aluminum oxide.
U.S. Pat. Nos. 3,649,693 and 3,923,892 disclose the preparation of ring alkylated aromatic amines by reacting an aromatic amine with an olefin in the presence of aluminum aniline, optionally including a Friedel-Crafts promoter. Reaction products included 2-ethylaniline, and 2,6-diethylaniline.
Stroh, et al., in U.S. Pat. Nos. 3,275,690; 2,762,845, Japanese No. SHO 56-110652, and, as mentioned previously, AS No. 1,051,271, disclose various processes for preparing alkylated aromatic amines by reacting an aromatic amine with an olefin in the presence of Friedel-Crafts catalysts as well as a combination of the Friedel-Crafts catalysts in the presence of halogen compounds combined with aluminum. Representative reaction products included 2-cyclohexylaniline, diethyltoluenediamine, diethylaniline, diisopropylaniline and mono-tert-butylaniline.
The art, e.g., Netherlands Application No. 6,407,636 has recognized that alkylation of various aromatic and heterocyclic compounds can be carried out in the presence of a zeolite having a port size greater than 6 Angstroms wherein active cationic sites are obtained with exchangeable metal or hydrogen cations in their ordered internal structure.
French Pat. No. 1,406,739, which is equivalent to Netherlands Application No. 6,407,636, discloses the preparation of alkylated aromatic compounds having polar substitutions thereon utilizing alumino-silicates having a pore size of at least 6 Angstroms as a catalyst. Cations of low valence were deemed to have been particularly effective for the ring alkylation of aromatic compounds having weakly basic substituents such as aromatic amines. The examples show the alkylation of aniline with propylene in the presence of a sodium zeolite X and alkylation of diphenylamine with propylene in the presence of a molecular sieve 13X which has undergone a partial exchange with rare earths and having a pore size of 7-8 Angstroms.
U.S. Pat. No. 3,201,486 discloses processes for alkylating various aromatic hydrocarbons with an olefin using sulfuric acid and hydrogen fluoride as a catalyst. In the particular reference solid phosphoric acid was used as the catalyst.
Although the prior art has disclosed that a variety of catalytic systems can be utilised in the alkylation of aromatic hydrocarbons and aromatic amines, the art also teaches that a variety of reaction products are produced, including both ortho and para-isomers of mononuclear aromatic amines as well as, mono, di and tri alkyl substituted amines. In addition the prior art teaches that neutral to weakly acidic catalysts are preferred for effecting ring alkylation of the aromatic amines. Even though the prior art has suggested preferred catalytic system such systems also involve batch, liquid phase operation which may be difficult to operate over an extended period of time, and tend to give more para product. In addition, many of the processes suffer from poor conversion, poor reaction rate and an inability to produce high ortho to para isomer ratios at high conversion.
U.S. Pat. No. 4,310,440 describes a novel class of molecular sieve materials. These materials are aluminophosphates (ALPO's) and consist of alternating tetrahedra of Al and P. The tetrahedra are linked together in such a way as to provide microporus crystalline structure to the material. These materials are best described as non-zeolitic molecular sieve materials. Although the structures of some of the ALPO compositions are analogous to the known zeolite materials, several novel structures within this class of materials have been identified.
Other new materials based on the aluminophosphate family of molecular sieves have been described and patented in numerous U.S. and E.P. patents and patent applications. For example, U.S. Pat. No. 4,440,871 describes a member of the class of aluminophosphates that are generated by the substitution of Si for Al or P into the ALPO structure. These silicoaluminophosphates (SAPO's) have ion exchange properties formed by the substitution of the tetravalent Si for the trivalent Al or pentavalent P. These materials when exchanged with protons exhibit the protonic acidities normally observed for zeolites. Likewise, other materials in this class containing Ti, Cr, B, Mg, Co, and other metallic component substituted for Al and P have been prepared and described in the following patents: EP No. 121232 (TAPO's), EP No. 132708 (metalloaluminophosphates, MeAPO's), EP No. 131946 (FAPO's).
The use of these materials in hydrocarbon and alcohol conversion processes is described in several patents issued to Union Carbide Corporation. U.S. Pat. No. 4,499,316 describes the use of ALPO's in the conversion of olefins to aromatic hydrocarbons. EP No. 124119 describes compositions containing SAPO's for the conversion of petroleum feedstocks to lighter fractions, i.e. hydrocracking. U.S. Pat. No. 4,527,001 describes the use of non-zeolitic crystalline molecular sieves of this class as catalysts for the interconversion of light olefins. U.S. Pat. No. 4,499,315 describes the conversion of hydrocarbons to aromatics using SAPO materials as a catalyst. U.S. Pat. No. 4,499,316 describes the use of ALPO's for a similar conversion process.